Dredging apparatus.



H. s. TAFT & U. THOMPSON, JB. DREDGING APPARATUS.

AIPLIGATION FILED JAN. 13,1908.

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DRED'GING APPARATUS. APPLICATION FILED JAN. 13,1908.

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No. 890,470. PATENTED JUNE 9, 1908. H. S. TAPT da U. THOMPSON, Jn.

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DREDGING APPARATUS.

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No. 890,470. PATENTD-JUNE 9, 1908', H. S. 'TAFT & U. THOMPSON, JR.DREDGING APPARATUS.

APPLIGATION FILED JAN.13,190B.

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No. 890,470. v PATENTED JUN 9, 1908. H. S. TAFT & U. THOMPSON, JB.

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' H. S. TAFT & U. THOMPSN, JB.

DREDGING APPARATUS.

APPLICATION FILED JAN.13,1908.

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No. 890,470. PATENTED JUNE 9, 1908. H. S. TAPT & U. THOMPSON, JR.

DREDGNG APPARATUS.

APPLICATION FILED JAN.13.1908.

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UNITED STATES PATENT OFFICE.A i

HARRISON SOUTHWICK TAFT, OF NEW YORK, N. Y., AND ULDRIC THOMPSON, IR.,OF HONOLULU, TERRITORY OF HAWAII.

DREDGING APPARATUS.

Specification of Letters Patent.

Patented June 9, 1908 Application filed January 13, 1908. Serial No.410,512.

To aZZJwhom it may concern:

Be it known that we, HARRISON SOUTH- wrox TAFT, of the city, county, andState of New York, and ULDRIC THOMPSON, Jr., of Honolulu, Territory ofHawaii, citizens of the United States, have invented new and usefulImprovements in Dredging Apparatus, of which the following is aspecification.

Our invention relates to the practice of dredging waterways,particularly canals and channels, and consists in apparatus applicableto dredges whereby the control over the dredging operations is improvedand accuracy and Jfacility of operation secured.

As a type of dredging apparatus to which our invention is applicable, weselect for illustration a rotary-cutter or boring dredge. The presentmode of operation of such a dredge involves fixing or mooring thel'loating hull thereof by means of anchored sidel guys and a verticaltimber called the spud, which, when xed in the bottom of the canal,channel, or other body of water, serves as a )ivot on which the dredgemay be moved laterally in the waterway. The s uds are located at or nearthe end of the hul farthest 'from the cutter, which is suspended on theend of a vertically movable arm, called the ladder; the cutter isrotated by machinery located in the hull, and cuts away earth insuccessive arcs, as the dredge hull is swung -from side to side aboutthe depressed spud as a center. Wire cables, running to anchors fixed atconvenient points on either side of the dredge, serve to im art thelateral swinging movement to the c redge, the machinery which operatesthese cables being under the control of the man who guides the movementsof the dredge. In cutting canals or channels, a cross-section of thecanal or channel is determined on, and the dredge set to work toexcavate in accordance with the said cross section. The depth to whichthe dredge cutter is allowed to fall determines the vertical dimensionof excavation, and the amount of lateral `movement of the dredgedetermines the lateral dimension.

When a section of' the excavation has been cut, the dredge is movedforward by sinking another spud ahead o'l the one last employed, raisingthe latter, and moving the second spud aft on the dredge, thus movingthe dredge ahead. As the dredge cutter works for the most part underwater, it is diHicult for the lever man, who directs the movements ofthe dredging machinery, to guess with any degree of certainty how nearthe cutter is operating to the prescribed cross section. Thisuncertainty is increased when the [inishing act is given to a channelrequiring an inclined. side, as the lever man has to give the cutter itsvertical adjustment while the dredge hull isgiven its lateral movement;the securement of an accurate resultant motion is largely a matter ofchance. Many arrangements of sighting flags and guide poles have beenemployed to assist the eye of the operator' in making his adjustments,but these have never, so far as we are aware, given much satisfaction.

Our invention consists in an arrangement of apparatus in combinationWith the elementary dredge mechanism, whereby a tracer or pointer, inview of the lever man, shows at all times on a table or diagramsheet,the exact location of the dredging cutter in relation to a predeterminedcross section of excavation. The excavation outline may be drawn inreduced scale on the diagram-table, and the movements of the tracer arethen reduced in the same ratio, as compared with the movements of thedredge and its cutter. This arrangement, presently to be described indetail, enables the lever man to direct his operations exactly as thoughhe could see the cutter at all times and had visible guides in the earthto show exactly the limits of cut..

In the drawings hereto annexed, which illustrate forms in which ourinvention may be embodied, Figure 1 is a longitudinal elevation of acutter dredge, showing a mode of applying and operating our invention;Fig. 2 is a plan view of the dredge shown in Fig. 1; Fig. 3 is a planview, on a larger scale than that used for Figs. 1 and 2, of the diagramtable and tracer which forms a part of our invention; Fig. 4 is a sideelevation of the diagram table and tracer shown in Fig. 3; Fig. 5 is aplan view, also on a liberal scale, of the manually operated sightingdevice included in Figs. 1 and 2; Fig. 6 is a side elevation of thesighting device illustrated in Fig. 5; Fig. '7 is a plan view of thereducing motion between the cutter ladder and tracer 3 Fig. 8 is a sideelevation of the detail shown in Fig. 7; Fig` 9 is an automaticgyroscopic sighting device, shown in plan Fig. 10 is a side elevation ofthe device shown in Fig. 9 Fig. 11 is a plan view of a compass bowl andattachments which may be employed in connection with the apparatus; andFig. 12 is a cross sectional view, showing the dredge and a typicalchannel cross section.

Referring to Figs. 1 and 2, S represents the hull of a dredge, A thecutter ladder, A the cutter, D the A-frame on which the cutter operatingAblocks are hung, S the leverhouse which contains the controlling linesfor operating the dredge and its cutter, J one of the spuds, shown asdepressed into the channel-bottom and serving as the pivot on which thedredge turns laterally.

At some point within easy observation distance from the man in thelever-house, a table T is iixed, on which a sheet of paper ordiagramward may be secured. A tracer, G, is movably mounted over thetable T, and operated as follows:

From some convenient point on the cutter ladder, a wire B is led to thedrum E, pivoted on the frame D. A counterweight H is suspended from thedrum E by a wire in such manner that the wire B is always kept taut.

From the shaft C of the drum E the wire F is led to the tracer G andthence to a counterweight l, which holds wire F suitably taut.

treme up and down movement of the ladder A, may'not carry the tracerbeyond the margins of the table. The movement of the cutter A will beara substantially constant ratio to that ofthe tracer G, the deviation dueto the circular movement of the ladder A is not of any practicalconsequence in the dredging operation.

In order to communicate to the tracer G a movement over the table Twhich shall correspond with the lateral swing of the dredge, we provide,in the arrangement shown in Figs. y1 and 2, a manually operated sightingdevice. On a platform O there is mounted a stand N on which thehorizontal bar M is pivoted. At N there is provided a handle and at R aroller on a circular' track concentric with the pivot on which the bar Mturns. Sights a, a are mounted on the'bar M at a suitable elevation,sight a being directly over thepivot and sight a near the forward end ofthe bar. The pivot of bar M consists of a vertical shaft which issecured to bar H and extends down to a sector L, from which a wireLextends forward to thecarriage on which the tracer G is mounted. Thedetails ofv this mechanism will presently be described suffice it to sayfor the present that the horizontal component of movement of the tracerG is communicated from the sighting device which, as the dredge swings,is kept pointed at some fixed distant object, as the flag a2, andconsequently swings with relation to the dredge, while the verticalcomponent of movement of the tracer G is communicated.

from the ladder A by means of the reducing motion above described in itsmere elements. Whatever may be the ratio of reduction of these twocomponent movements, it is clear that the tracer G, so long as thesights (1 a are kept trained on the flag c2, will correctly representthe position of the cutter A. ll', therefore, a cross section of thechannel to be cut is laid out to proper scale on the diagram table T, solong as the tracer G is kept within the limits of the cross sectionalchart, the cutter will be sure to (merate within its proper range andthe lever man in control of the dredge can gage the lateral swingcorrectly, checking the swing when the tracer comes to the line which,on the diagram, represents the side of the excavation to be made. A manstationed at N has only to keep his` sights e, e always trained on'the[lag e2. As the cutter A is lowered from time to time to take deepercuts in the earth, the tracer G will move downward on the diagram, and,as the sides of the channel will probably be sloping, the angle of swingof the dredge will diminish as the critter' A moves from one level tothe next. Then the rough cuts have been made in the excavation, thesloping sides of the channel are smoothed by a slanting cut. ln thisoperation the lever man will be greatly assisted by the tracer G byobserving its movement along the line of the diagram he can adjust therate of swing to the rate of vertical movement of the cutter A so thatthe resultant 'movement of the eutter will make a true slanting cut, andnot cut too lightly at one place and gouge too deeply at another. y

Vhen the cross section of channel is cut, the dredge is spudded ahead inthe manner described. in the same fore-and-aft line on the dredge, thelateral shift of the center of swing is not great enough to make anypractical dill'erence in the operation of the sighting device. A dredgeis not an instrument of precision, and the demands on it for accuracyare moderate. As heretofore operated, however, the errors in excavationhave often been serious and costly to repair; the employment of the.within described invention insures rn'ecision of operation up to thecapacity of the dredg ing apparatus as a whole, and enables the leverman to accomplish easily what heretofore would have beenA considered thefeat ol' an expert.

The details of the apparatus above described in general are as follows:Fig. 3 shows in plan and Fig. 4l: in elevation the diagram table andtracer which, as shown in Figs. Vl and 2, is located immediately vin theview oll the man controlling the dredge levers. The tracer itself, G, ismounted to slide in a guide G and its sliding movement in this guide isgoverned by the wire F leading from the .re ducing motion on the`A-frame. This wire Though ythe spuds J are not i guide G over thediagram board T.

passes over the pulley G2, thence Ito the pointer G, to which it issecured, and continues over the pulley G3 to the counterweight I whichserves to keep the wire stretched tight. As the dredge cutter moves upor down, the above described connections cause the pointer of the tracerG to move up or down in the This diagram board is shown as adjustablysecured to the frame or table T and, as shown in Fig. 3, a diagram ofthe cross section of the excavation is laid out and the various cuttinglevels are marked and numbered thereon. The lateral traverse of thetracer G over the excavation diagram` is secured by movement of theguide G laterally over the board T. This guide is provided at its basewith rollers g, g, g, g, which run on either side of the track G4, thistrack being secured to some stationary base. Wires lead from the rollerportion of the guide G over suitable pulleys to the lateral movementactuator which, as shown in Figs. l and 2, may be a manually operatedsighting device, or, as shown in Figs. 9 and 10, an automatic "sightingdevice which maintains its position irrespective of movements of thedredge.

Referring to Figs. 5 and 6, which show on an enlarged scale the manuallyoperated sighting device indicated in Figs. l and 2, the wires L, whichare secured to the traversing tracer guide (Figs. 3 and 4) pass over theguide pulleys L5, L4, L3, L2, to the quadrant or sector L. This sectoris secured to the vertical shaft N2 mounted on a frame N, this framebeing located on the sighting platform O. The shaft N2 is located midwaybetween the spuds J and secured to this shaft is the arm M which has atits rear end the operating handle N and at its forward end the roller Rwhich travels on the track R. Directly over the shaft N2 there is placedthe sight a and directly over the roller R the sight a is located. Theoperating handle N works over a circular arc N3 which may be provided,as shown in Fig. 5, with a series of holes n3 for the reception of plugsor stops to limit the lateral swing of the arm M. These plugs or stopsand the arm M may conveniently be made to carry contact points for anelectric signaling circuit, so that in addition to the traversing tracerG, the man in control of the dredge may be given a warning as by theringing of a bell whenever the sighting lever has reached the prescribedlimit of its lateral swing.

Referring now to Figs. 7 and 8: these figures illustrate on an enlargedscale the reducing motion from the cutter ladder A to the tracer G` Thewire B secured at its lower end to the cutter ladder A is secured to andwound ,upon the drum E which is keyed to the shaft C. Another drum Ecarries the counterweight wire B to which the counterweight H issecured. The wire F which leads to the tracer is secured to and woundupon the shaft C. Thus, the difference in diameter as between the shaftC andl the drum E determines the ratio of reduction, in other words, thescale of the tracer diagram on the tracer board T. (See Figs. 4 and 5).

Obviously the employment of a manually operated sighting device such asillustrated in Figs. 5 and 6, involves the employment of a man to standat the sighting device and operate it. As it may be advisable todispense with the services of a man at the sighting device, both forreasons of economy and also for the reason that constant watchfulness isthe price of accurate service of this character, we have shown in Figs.9 and 10 an automatic sighting device which may be located at anyconvenient point` on the dredge. A heavy 'ily wheel l/V is mounted onthe shaft w in the swiveling frame TV, this frame being mounted oncolumns TN which swivel on the base W4, an antifriction ball or rollerbearing W5 being preferably supplied. The sector L is secured to thecolumns W and carries the wires L as in the manually operated deviceshown in Figs. 5 and 6. The fly wheel TV is rapidly rotated by means ofan electric motor WV" and on the end of the shaft farthest from themotor WV? a fly wheel W may be attached to balance the weight of themotor. The frame W3 is turned by hand upon the base W74 until the tracerG is observed to be in a position which corresponds exactly with theposition of the dredge cutter in the excavation and then the .motor VWis started. The rapid rotation of the fly wheel W supplemented by thatof the rotor of the motor W`-" and the counterbalancing fly wheel V,)reserves the direction in which this sighting frame was originally setand if the motor W2 be kept in operation while the dredge is at work,the movement of the tracer G laterally over the diagram table willcorrespond exactly to the movement of the dredge cutter in theexcavation.

As an additional guide for the man in control of the dredge levers, weprovide an attachment to a mariners compass such as shown in Fig. 11,wherein Y is the compass bowl and Y a card which maybe placed upon theordinary compass card. represents the usual fixed point or lubbers markin the compass bowl. The card Y is provided with radial markings whichcorrespond to the lateral angular swing of the dredge necessary to makethe excavation cuts at the different levels. As the dredge swings theapproach of the scale markings on card Y to the lubbers mark Y gives theoperator notice in addition to the devices already described of theapproach of the cutter to the proper limit of its lateral swing.

What we claim and desire to secure by Letters Patent is:

l. The combination in a laterally movable dredge, of a verticallyadjustable dredging instrument, a diagram table mounted on the dredge, atracer movable over the diagram table, and connections between thetracer and the dredging instrument to change the position of the tracerin relation to the table as the dredging instrument is raised orlowered.

2. The combination in a laterally movable dredge, of a verticallyadjustable dredging instrument, a diagram table mounted on the dredge, atracer movable over the diagram table, and connections between thetracer and the dredging instrument to change the position of the tracerin relation to the table as the dredging instrument is raised orlowered, and means mounted on the dredge to disclose the amount oflateral movement of the dredge.

8. The combination in a laterally movable dredge, of a diagram tablemounted on the dredge, a tracer movable over the diagram table, apivoted sighting device and connections therefrom to the tracer, to movethe tracer in relation to the table as the angular relation of thedredge and sighting device changes.

4. The combination in a laterally movable dredge, of a diagram tablemounted on the dredge, a tracer movable over the diagram table, apivoted sighting device and connections therefrom to the tracer to movethe tracer in relation to the table as the angular relation of thedredge and sighting device changes, a vertically adjustable dredginginstrument, and connections therefrom to the 'tracer to change theposition of the tracer in relation to the table as the dredginginstrument is raised or lowered.

5. The combination in a laterally movable dredge, of a verticallyadjustable dredging instrument, a diagram table mounted on the dredge, adiagram board adjustably secured to said table, a tracer mounted oversaid diagram table, and connections between the tracer and the dredginginstrument to change the position of the tracer in relation to the tableas the dredging instrument is raised or lowered.

6. The combination in a laterally movable dredge, of a diagram tablemounted on the dredge, a diagram board adjustably secured to said table,a pivoted sighting device and connections therefrom to the tracer tomove the tracer in relation to the table as the angular relation of thedredge and sighting device changes.

7. The combination in a laterally movable dredge, of a cutter ladder, avertically adjustable dredging instrument suspended therefrom, a'diagramtable mounted on the dredge, a tracer movable over the diagram table, areducing motion, connections therefrom to said cutter ladder and saidtracer, to change the position of the tracer in relation l to the tableas the dredging instrument is raised or lowered.

8. The combination in a laterally movable dredge, of a cutter ladder, avertically adjustable dredging instrument suspended therefrom, a diagramtable mounted on the dredge, a tracer movable over the diagram from tosaid cutter ladder and said tracer, to change the position of the tracerin relation to the table as the dredging instrument is raised orlowered, and means mounted on the dredge to disclose the amount oflateral movement of the dredge.

9. The combination in a laterally movable dredge, of a cutter ladder, avertically adjustable dredging instrument suspended therefrom, a diagramtable mounted upon the dredge, a tracer movable over the diagram table,a reducing motion, comprising a shaft, a plurality of drums mounted onsaid shaft, a flexible connection wound upon one of said drums andhaving its upper end secured thereto and its lower end secured to saidcutter ladder, a Vflexible band carrying a counterweight wound upon andsecured to another of said drums, a flexible connection Secured at oneend to said tracer and having its other end secured to and wound aroundsaid shaft, said reducing motion adapted to change the position of thetracer with relation to the table as the dredging instrument is raisedor lowered.

10. The combination in a laterally movable dredge, of a cutter ladder, avertically adjustable dredging instrument suspended therefrom, a diagramtable mounted upon the dredge, a tracer movable over the diagram table,a reducing motion comprising a shaft, a plurality of drums mounted onsaid shaft, awire wound upon one of said drums and having its upper endsecured thereto and its lower end secured to said cutter ladder, a wirecarrying a counterweight wound upon and secured to another of saiddrums, a wire secured at one end to said tracer and having its other endsecured to and wound around said shaft, said reducing motion adapted tochange the position of the tracer with relation to the table as thedredging instrun'ient is raised or lowered, and means mounted on thedredge to disclose the amount of lateral movement of the dredge.

1l. The combinationin a laterally movable dredge, of a verticallyadjustable dredging instrument, a reducing motion actuated by verticalmovement of the dredging instrument, a diagram table mounted on thedredge, a guide secured over said table, a tracer slidably mounted insaid guide, a plurality of pulleys mounted on said guide, a wire leadingfrom said reducing motion pass ing over one of said pulleys, secured tosaid tracer and continuing over another of said pulleys and having acounterweight at its table, a reducing motion, connections tliereend,said tracer adapted to move up or down in said guide as the saiddredging instrument is raised or lowered.

12. The combination in a laterally movable dredge, of a verticallyadjustable dredging instrument, a reducing motion actuated by saiddredging instrument, a diagram table mounted on the dredge, a guide'secured over said table, a tracer slidably mounted in said guide, raplurality of pulleys mounted on said guide, a wire leading from saidreducing motion passing over one of said pulleys, secured to said tracerand continuing over another of said pulleys and having a counterweightat its end, said tracer adapted to move up or down in said guide as saiddredging instrument is raised or lowered, and means mounted on saiddredge to disclose the amount of lateral movement of the dredge.

13. The combination in a laterally movable dredge, of a cutter ladder, avertically adjustable dredging instrument suspended therefrom, a frame,a shaft mounted on said.

- base, a shaft, a 'fly wheel mounted on said frame, a plurality ofdrums mounted on said shaft, a wire wound upon one of said drums havingitsA upper end secured to said drum and its lower end secured to saidcutter ladder, a wire carrying a counterweight wound upon and secured toanother of said drums, a diagram table mounted on the dredge, a guidemounted over said table, a tracer slidably mounted in said guide, aplurality of pulleys mounted on said guide, a wire wound around saidshaft and having one end secured thereto, said wire passing over one ofsaid pulleys, secured to said tracer and continuing over another of saidpulleys and having a counterweight at its end, said tracer adapted tomove up or down in said guide as the said dredging instrument is raisedor lowered.

14. The combination in a laterally movable dredge, of a cutter ladder, avertically adjustable dredging instrument suspended therefrom, a frame,a shaft mounted on said frame, a plurality of drums mounted on saidshaft, a wire wound upon one of said drums having its upper end securedto said drum and its lower end secured to said cutter ladder, a wirecarrying a counterweight wound upon and secured to another of saiddrums, a diagram table mounted on the dredge, a guide mounted over saidtable, a tracer slidably mounted in said guide, a plurality of pulleysmounted on said guide, a wire wound around said shaft and having one endsecured thereto, said wire passing over one of said pulleys, secured tosaid tracer and continuing over another of said pulleys and having acounterweight at its end, said tracer adapted to move up or down in saidguide as the said dredging instrument is raised or lowered, and meansmounted on the dredge to disclose the amount of lateral movement of thedredge.

15. The combination in a laterally movable dredge, of a diagram tablemounted on the dredge, a tracer movable over the diagram table, agyroscopic sighting device and connections therefrom to the tracer tomove the tracer in relation to the table as the angular relation of thedredge and sighting device changes.

16. The combination in a laterally movable dredge, of a diagram tablemounted on the dredge, a tracer movable over the diai gram table, agyroscopic sighting device, conj nections therefrom to the tracer tomove the tracer in relation to the table as the angular relation of thedredge and sighting device changes, a vertically adjustabledredginginstrument, and connections therefrom to the tracer to changethe position of the tracer in relation to the table as the said dredginginstrument is raised or lowered.

17. The combination in a laterally movable dredge, of a diagram tablemounted on the dredge, a tracer movable over the diagram table, agyroscopic sighting device comprising a base, a column swiveled on saidshaft, a motor mounted on said shaft, and connections from said sightingdevice to said tracer to move the tracer in relation to the table as theangular relation of the dredge and sighting device changes.

18. The combination in a laterally movable dredge, of a diagram tablemounted on the dredge, a tracer movable over the diagram table, agyroscopic sighting device comprising a base, a column swiveled on saidbase, a shaft, a fly wheel mounted 011 said shaft, a motor mounted onsaid shaft, connections from said sighting device to said tracer to movethe tracer in relation to the table as the angular relation of thedredge and sighting device changes, a vertically adjustable dredginginstrument, and connections therefrom to the tracer to change theposition of the tracer in relation to the table as the dredginginstrument is raised or lowered.

19. The combination in a laterally movable dredge, of a diagram tablemounted on the dredge, a base, a track secured to said base, a guidemounted over said table, said guide provided at its base with aplurality of rollers adapted to run upon either side of said track, atracer mounted in said guide, a gyroscopic sighting device, andconnections therefrom to said tracer to move the tracer in relation tothe table as the angular relation of the dredge and sighting devicechanges.

20. The combination in a laterally movable dredge, of a diagram tablemounted on thedredge, a base, a track secured to said base, a guidemounted over said table, said guide provided at its base with aplurality of rollers adapted to run upon either side of said track, atracer mounted in said guide, a gyroscopic sighting device, andconnections therefrom to said tracer to move the tracer in relation tothe table as the angular relation of the dredge and sighting devicechanges, a vertically adjustable dredging instrument and connectionstherefrom to the tracer to change the position of the tracer in relationto the table as the dredging instrument is raised or lowered.

21. The combination in a laterally movable dredge, of a diagram tablemounted on the dredge, a base, a track secured to said base, a guidemounted over said table, said guide provided with a plurality of rollersadapted to run upon either side of said track, a tracer mounted in saidguide, a gyroscopic sighting device comprising a base, a column swiveledon said base, a shaft, a fly wheel mounted on said shaft, a motormounted on said shaft, a sector mounted on said column, connections fromsaid sector to said guide to move the tracer in relation to the table asthe angular relation of the dredge and sighting device changes.

22. The combination in a laterally movable dredge, of a diagram tablemounted on the dredge, a base, a track secured to said base, a guidemounted over said table, said guide provided with a plurality of rollersadapted to run upon either side .of said track, a tracer mounted in saidguide, a gyroscopic sighting device comprising` a base, a columnswiveled on said base, a shaft, a fly wheel mounted on said shaft, amotor mounted on said shaft, a sector mounted on said column,connections from said sector to said guide to move the tracer inrelation to the table as the angular relation of the dredge and sightingdevice changes, and a vertically adjustable dredging instrument andconnections therefrom to the tracer to change the position of thetracerin relation to the table as the dredging instrument is raised orlowered.

23. The combination in a laterally movable dredge, of a cutter ladder, avertically adjustable dredging instrument suspended therefrom, a diagramtable mounted on the dredge, a tracer movable over the diagram table, aframe, a reducing motion mounted upon said frame, connections therefromto said cutter ladder and said tracer to change the position of thetracer in relation to the table as the dredging instrument is raised orlowered, a gyroscopic sighting device, and connections therefrom to saidtracer to move said tracer in relation to the table as the angularrelation of the dredge and sighting device changes.

24. The combination in a laterally movable dredge, of a cutter ladder, avertically adjustable dredging instrument suspended therefrom, a diagramtable mounted on the dredge, a tracer movable over the diagram table, aframe, a reducing motion mounted upon said frame, connections therefromto said cutter ladder and said tracer to change the position of thetracer in relation to the table as the dredging instrument is raised orlowered, and a gyroscopic sighting device comprising a base, a columnswiveled on said base, a shaft, a fly wheel mounted on said shaft, amotor mounted on said shaft, and connections from said sighting deviceto said tracer to move the tracerl in relation to the table as theangular relation of the dredge and sighting device changes.

25. The combination in a laterally movable dredge, of a cutter ladder, averticalljv adjustable dredging instrument suspended therefrom, adiagram table mounted upon the dredge, a tracer movable over the diagramtable, a frame, a reducing motion comprising a shaft mounted on saidframe, a plurality of drums mounted on said shaft, a wire wound upon oneof said drums and having its upper end secured thereto and its lower endsecured to said cutter. ladder, a wire carrying a counterweight woundupon and secured to another of said drums, a wire secured at one end tosaid tracer and having its other end secured to and wound upon saidshaft, said reducing motion adapted to change the position of the tracerin relation to the table as the dredging instrun'ient is raised orlowered, and a gyroscopic sighting device and com'iections therefrom tosaid tracer to move said tracer in relation to said table as the angularrelation of the dredge and sighting device changes.

2G. The combination in a laterally movable dredge, of a cutter ladder, averticalljv adjustable dredging instrument suspended therefrom, adiagram table mounted upon the dredge, a tracer movable over the diagramtable, a frame, a reducing motion comprising a shaft mounted on saidframe, a plurality of drums mounted on said shaft, a wire wound upon oneof said drums and having its upper end secured thereto and its lower endsecured to said cutter ladder, a wire carrying a cmmterweight wound uponand secured to another of said drums, a wire secured at one end to saidtracer and 'having its other end secured to and wound upon said shaft,said reducing motion adapted to change the position of the tracer withrelation to the table as the dredging instrument is raised or lowered,and a gyroscopicsighting device comprising a base, a column swiveled onsaid base, a shaft, a fly wheel mounted on said shaft, a motor mountedon said shaft, and connections froln said sighting device to said tracerto move the tracer in relation to the table as the'angular relation ofthe dredge and sighting device changes.

27. The combination in a laterally movable dredge, of a verticallyadjustable dredging instrument, a frame, a reducing motion mounted uponsaid frame, a diagram table mounted on the dredge, a guide secured oversaid table, a tracer slidably mounted in said guide, a plurality ofpulleys mounted on said guide,y a wire leading from said reducing motionpassing over one of said pulleys and secured to said tracer andcontinuing over another of said pulleys having a counterweight at itsend, said tracer adapted to move up or down in said guide as the saiddredging instrument is raised or lower'ed, and a gyr'oscopic sightingdevice and connections therefrom to the tracer to move the tracer inrelation to the'table as the angular relation of the dredge and sightingdevice changes.

28. The combination in a laterally movable dredge, of a cutter ladder, avertically adjustable dredging instrument suspended therefrom, a frame,a shaft mounted on said frame, a plurality of drums mounted on saidshaft, a wire wound upon one of said drums having its upper end securedto said dr'um and its lower end secured to said cutter' ladder', a wir'ecarrying a counterweight wound upon and secured to another of saiddrums, a

diagram table mounted on the dredge, a

guide mounted over said table, a tracerI slidably mounted in said guide,a plurality of pulleys mounted on said guide, a wire wound around saidshaft and having one end secur'ed thereto, said wire passing over one ofsaid pulleys and secured to said tracer and continuing over another ofsaid pulleys and having a `counterweight at its end, said tracer'adapted to move up or down in said guide as the dredging instrument israised or lowered, and a gyroscopic sighting device and connectionstherefrom to the tracer to move the tracer in relation to the table asthe angular' relation of the dredge and sighting device changes.

29. The combination in a laterally movable dredge, of a verticallyadjustable dredging instrument, a fr'ame, a reducing motion mounted uponsaid frame, a diagram table mounted on the dredge, a guide secured oversaid table, a tracer' slidably mounted in said guide, a plurality ofpulleys mounted on said guide, a wire leading from said reducing motionpassing over one of said pulleys secured to said tracer and continuingover another' of said pulleys and having a counter- Weight at its end,said tracer adapted to move up or down in said guide as the saiddredging instrument is raised or lowered and a gyroscopic sightingdevice comprising a base, a column swiveled on said base, a shaft, a`fly wheel mounted on said shaft, a motor mounted on said shaft andconnections from said sighting device to said tracer to moveguide, abase, a track secured to said base, a plurality of rollers mounted onsaid guide and adapted to run on either side of said track, a pluralityof pulleys mounted on said guide, a wire leading from said reducingmotion passing over one of said pulleys, secured to said tracer' andcontinuing over another' of said pulleys, and having a counterweight atits end, said tracer vadapted to move up or down in said guide as thesaid dredging instrument is raised or lowered, and a gyroscopic sightingdevice and connections therefrom to said tracer to move the tracer inrelation to the table as the angular' relation of the dredge andsighting device changes.

31. The combination in a laterally movable dredge, of a verticallyadjustable dren ging instrument, a frame, a lreducing motion mounted onsaid frame, a diagram table mounted on j the dredge, a guide securedover said table, a tracer slidably mounted in said guide, a base, atrack secured to said basea plurality of rollers mounted on said guideand adapted to run on either side of said track, a plurality of pulleysmounted on said guide, a wire leading from said reducing motion passingover one of said pulleys secured to said tracer and continuing overanother of said pulleys, and having a counterweight at its end, saidtracer adapted to move up or down in said guide as thc said dredginginstrument is raised or lowered, and a gyroscopic sighting devicecomprising a base, a column swiveled on said base, a shaft, a fly wheelmounted on said shaft, a motor mounted on said shaft, a sector mountedon said column, connections from said sector to said guide to move thetracer' in relation to the table as the angular r'elation of the dredgeand sighting device changes.

32. The combination in a laterally movable dredge, of a cutter ladder, avertically adjustable dredging instrument suspended therefrom, a frame,a shaft mounted on said frame, a plurality of drums mounted on saidshaft, a wire wound upon one of said drums having its upper end securedto said drum and its lower end secured to said cutter' ladder, a wirecarrying a counterweight wound upon and secured to another of saiddr'ums, a diagram table mounted on the dredge, a guide mounted over saidtable, a tracer slidably mounted in said guide, a base, a track securedto said base, a plurality of rollers mounted on said guide and adaptedto run on either side lof said track, a plurality of pulleys ,mounted onsaid guide, a wire wound upon said shaft and having one end securedthereto passing over one of said pulleys and secured to said tracer andcontinuing over another of said pulleys `and having a counterweight atits end, said tracer adapted to move up or down in said guide as thesaid dredging instrument is raised or lowered and a gyroseopic sightingdevice Signed by us at Boston, Suilolk county, 10 comprising a base, acolumn swiveled on Massachusetts, this 'first day of January,

said base, a shaft7 a fly Wheel mounted on said 1908.

shaft, a motor mounted on said shaft, a sector r x H m mounted on saidcolumn, connections from l MM' said sector to said guide to move thetracer l t L' L l" in relation to the table as the angular relall/Vltnesses:

GDIN ROBERTS,

tion of the dredgev and sighting device v CHARLEs D. VVOODBERRY.

changes.

